 RU.HACKER (2:5020/299)  RU.HACKER 
 From : Urri Temkin                         2:5020/322.9    Mon 29 Aug 94 23:39 
 Subj : UMC82C491 Shadow memory dox w/sources.                                  


 ABS>> Hp.  p 㦥 p⭮   , H,
 ABS>>   : - 堪 UMC 稯  p
 ABS>>   subj? ,   ᪠, ⮡ ⠬ 뫮
 ABS>> Video BIOS Shadow 32  (, BIOS 祬- 㬥
 ABS>> ⮫쪮  64 ,    p  32)  㤠 䮭
 ABS>> ᠭ.   -  LastByte 릨,  
 ABS>> _㦥_    ?

 0c0 - xxxx xxxx - read only
 0c1 - ssww rfww
             DRAM wait states:
              00 - 2
              01 - 2
              10 - 1
              11 - 0
            page mode:
             0   - normal
             1   - fast
           refresh mode:
            0    - slow (refresh both DRAM and ISA bus)
            1    - fast (refresh only DRAM)
        cache write wait states:
         11      - 0
         10      - 1
         01      - 2
         00      - 2
      cache scheme:
       00 - 3-2-2-2
       01 - 3-2-2-2
       10 - 3-1-1-1
       11 - 2-1-1-1
 0c2 - xx?? ???x
               1 - enable external cache
             x   - read only
        1        - enable non-cachable block 1
       1         - enable non-cachable block 2
 0c3 - ??c? ????
        check ELBA# signal:
         0 - at T1
         1 - at T2
       x         - read only
 0c4 - t??? ????
       0         - turbo on
       1         - turbo off
 0c5 - non-cachable block 1 address (in 16k units)
 0c6 - non-cachable block 1 size (in 16k units)
 0c7 - non-cachable block 2 address (in 64k units)
 0c8 - non-cachable block 2 size (in 64k units)
 0c9 - mmmm mmmm - memory size
              xx - bank 0
            xx   - bank 1
         xx      - bank 2 (???)
       xx        - bank 3 (???)
      where xx:
       10 - 1M SIMM
       11 - 256K SIMM (???)
 0ca - ???? ???p
              parity check:
               0 - enabled
               1 - disabled
 0cb - x??? ????
        x        - read only
      memory remapping:
       0         - disabled
       1         - enabled
 0cc - ssss ????
         00      - 0e000-0efff disable shadow
         01      - 0e000-0efff enable non-cachable shadow
         10      - 0e000-0efff enable cachable shadow
         11      - 0e000-0efff enable RAM
       00        - 0f000-0ffff disable shadow
       01        - 0f000-0ffff enable non-cachable shadow
       10        - 0f000-0ffff enable cachable shadow
       11        - 0f000-0ffff enable RAM
 0cd - ssss ssss
              00 - 0cc00-0cfff disable shadow
              01 - 0cc00-0cfff enable non-cachable shadow
              10 - 0cc00-0cfff enable cachable shadow
              11 - 0cc00-0cfff enable RAM
            00   - 0c800-0cbff disable shadow
            01   - 0c800-0cbff enable non-cachable shadow
            10   - 0c800-0cbff enable cachable shadow
            11   - 0c800-0cbff enable RAM
         00      - 0c400-0c7ff disable shadow
         01      - 0c400-0c7ff enable non-cachable shadow
         10      - 0c400-0c7ff enable cachable shadow
         11      - 0c400-0c7ff enable RAM
       00        - 0c000-0c3ff disable shadow
       01        - 0c000-0c3ff enable non-cachable shadow
       10        - 0c000-0c3ff enable cachable shadow
       11        - 0c000-0c3ff enable RAM
 0ce - ssss ssss
              00 - 0dc00-0dfff disable shadow
              01 - 0dc00-0dfff enable non-cachable shadow
              10 - 0dc00-0dfff enable cachable shadow
              11 - 0dc00-0dfff enable RAM
            00   - 0d800-0dbff disable shadow
            01   - 0d800-0dbff enable non-cachable shadow
            10   - 0d800-0dbff enable cachable shadow
            11   - 0d800-0dbff enable RAM
         00      - 0d400-0d7ff disable shadow
         01      - 0d400-0d7ff enable non-cachable shadow
         10      - 0d400-0d7ff enable cachable shadow
         11      - 0d400-0d7ff enable RAM
       00        - 0d000-0d3ff disable shadow
       01        - 0d000-0d3ff enable non-cachable shadow
       10        - 0d000-0d3ff enable cachable shadow
       11        - 0d000-0d3ff enable RAM
 0cf - ???? ????
 0d0,0d4 - ?h?? ?rrr
                refresh divider:
                 000 - 64
                 001 - 1
                 010 - 2
                 011 - 4
                 100 - 8
                 101 - 16
                 110 - 32
           Hold PD(processor data) bus:
            0 - 1~2T
            1 - 2~3T
    x         - read only
 0d1,0d5 - ??kk kaaa
                ISA bus clock:
   111 - cpuclk/8
   110 - 7.2 MHz (doesn't work)
   101 - ???
   100 - cpuclk/2
   011 - cpuclk/3
   010 - cpuclk/4
   001 - cpuclk/5
   000 - cpuclk/6
            keyboard clock:
      11 1    - 7.2 MHz
      11 0    - 9.5 MHz
      10 1    - ???
      10 0    - cpuclk/2
      01 1    - cpuclk/3
      01 0    - cpuclk/4
      00 1    - cpuclk/5
      00 0    - cpuclk/6
 0d2,0d6 - dlrd rrrr
               IO recovery time (local I/O time/ISA I/O time):
                1111 - 12/12
                1110 - 9/9
                1101 - 7/7
                1100 - 5/5
                0111 - 12/3
                0110 - 9/3
                0101 - 7/3
                0100 - 5/3
                0011 - 3/3
                0010 - 2/2
                0001 - 1/1
                0000 - 0/0
             delay 0WS# signal by 1/2 ISA bus clock:
              0 - disabled
              1 - enabled
            RC emulation:
             0 - disabled
             1 - enabled
           LOWA20# emulation:
            0 - disabled
            1 - enabled
          DMA/master data location:
           0 - ISA
           1 - VLB
 0d3,0d7 - ???? ????

P.S. ᫨ ,   337 AKA 340.12.   ᠫ ⠪
     pp  UMC491, OPTI, FOREX (may be SIS).

--- GEcho 1.02+
 * Origin:  Why not ?  (2:5020/322.9)

